Investigations and parametric optimization of weld joint strength between tungsten copper and SS310 with copper interlayer in friction welding

Friction welding, a solid-state method, is a simple, economical, and productive approach to joining dissimilar metals. It overcomes the problems associated with conventional fusion joining techniques. It is extensively used in various applications in the automotive, aerospace, and medial fields. Rotary friction welding between dissimilar metals provides better results than rotary friction welding between similar metals. In this context, rotary friction welding is performed between two dissimilar materials, i.e., tungsten-copper (W/Cu-80/20) and stainless steel (SS310), using copper as an interlayer. Rotary friction welding is carried out on FWT-20 machine by varying the welding parameters. The effect of change in rotary friction welding parameters, namely rotating speed, upset pressure, and friction pressure, on tensile strength and hardness of obtained weld joint is investigated. Taguchi L₉ orthogonal array has been utilized to obtain experimental design. It is observed form the hardness measurement that the W/Cu has a hardness value of about 328 HV, while the SS316 side has a hardness of about 312 HV. Notably, the results shows that the hardness values decreased with distance from the weld interface. The ultimate tensile strength test is measured, followed by welding experiments. The results demonstrated the highest tensile strength of 315 MPa at 1 bar friction pressure, 4 bar upset pressure and speed of 1800 rpm, resulting in most suitable parametric combination. From statistical analysis performed using analysis of variance, it is observed that the spindle speed contributes significantly to achieving the desired output compared to other welding parameters.